The present invention relates generally to disposable tumblers and in particular to injection blow-molded tumblers of various configurations having a fortified rim at the upper extremity of the sidewall.
Disposable polymeric articles for packaging, bowls and cups are well known. Such articles are formed of polystyrene, polypropylene, polyethylene terephthalate and the like and may be made by thermoforming, injection molding, injection blow-molding, or other suitable technique. Injection molding has advantages in that a short cycle time is readily achieved, but tends to be more expensive in terms of material and articles so formed tend to have anisotropic properties and therefore exhibit brittleness. Thermoforming likewise tends to have advantageous cycle times, however, the waste generated tends to be excessive. Moreover, the draw which may be imposed on the sheet is limited. U.S. Pat. No. 5,693,278 discloses thermoformed articles produced from polyethylene terephthalate sheet. The excessive waste problem is addressed in the ""278 patent by utilizing at least forty percent (40%) by weight recycled material.
U.S. Pat. No. 5,433,337 of Willbrandt discloses an injection molded drink container to fit in vehicle cup holders. The container has an upper rim 20 with a height of from about {fraction (1/16)} of an inch to about {fraction (1/10)} of an inch and a width of from about 0.15 inches to about 0.25 inches. Note Col. 5 at lines 15-25. U.S. Pat. No. 5,427,269 notes at Col. 5 that this type of container may be produced by an suitable method, but that injection molding is preferred.
As noted hereinabove, injection molding tends to be expensive in terms of material, requiring relatively thick-walled parts to compensate for the anisotropy inherent in the production technique. Disposable containers are preferably made utilizing as little material as possible.
Many consumers are generally reluctant to use conventional disposable drinking cups on a frequent basis due to their xe2x80x9clook and feelxe2x80x9d, their expense, or their performance. Survey data indicate that consumers in many instances prefer disposable articles whose appearance and performance more closely resemble glassware. Conventional disposable drinking cups produced by blow-molding typically rely upon a relatively prominent curled rim to provide rigidity to the article and accordingly, the article does not resemble glassware to the extent desired. Moreover, even with the prominent top-curl, conventional blow-molded cups typically are not rigid enough to mimic glassware. Injection blow-molding processes and apparatus are widely known and widely used in industry. For example, reference may be had to U.S. Pat. No. 3,183,552 to Farkas, U.S. Pat. No. 3,819,314 to Marcus, U.S. Pat. No. 3,339,231 to Piotrowski and Canadian Patent No. 995,418 to Cannon et al.
It is known, in general, to use injection blow-molding of polycarbonates to produce an assortment of containers. See Kirk-Othmer Encyclopedia of Chemical Technology, Fourth Edition, Vol. 19, p. 600. Further, U.S. Pat. No. 4,139,517 discloses reusable milk bottles composed of aromatic polycarbonates and is specifically directed to a tinted polycarbonate container to prevent milk spoilage caused by artificial light or sunlight. The patent discloses that the containers can be prepared by well-known techniques, such as extrusion blow-molding, injection blow-molding, rotational molding, thermoforming, injection molding and lamination. No specific processing conditions for the mentioned molding techniques are given.
U.S. Pat. Nos. 4,225,304; 4,230,298; 4,234,302 and 4,308,086, issued to Valyi, disclose a continuous process and apparatus for blow-molding, including injection blow-molding, containers formed of various plastics including polycarbonates. Again, no specific process parameters for producing polycarbonate containers are provided. It is and has been a long standing objective of blow-molding processes to achieve a high productivity, i.e., to develop a process with a rapid, efficient and economical operating cycle.
State of the art processes known heretofore are subject to one or more significant disadvantages. Frequently, they are characterized by a relatively slow operating cycle. A shorter operating cycle is particularly desirable since it is directly translatable into a larger number of end products produced. Processes are known with overlapping cycles in order to reduce overall cycle time, for example, by providing that while one parison is being molded another is being blown and still another is being removed. However, even with processes using overlapping cycles the overall cycle time still leaves much to be desired and still necessitates improvement in cycle time. The foregoing difficulties are further compounded by frequent lack of reliability of prior art processes necessitating frequent interruptions of the operation and thereby further impairing operating efficiency.
U.S. Pat. No. 4,540,543 assigned to Canada Cup, Inc., a subsidiary of Fort James Corporation, discloses an injection blow-molding process and apparatus for hollow plastic articles. The method and apparatus for injection blow-molding hollow plastic articles is characterized by a rapid and efficient operating cycle. The injection mold includes a mold cavity and the blow mold is located adjacent the mold cavity in a side-by-side relationship. The parison is injection molded into the mold cavity onto a core. The parison on the core is separated from the mold cavity by moving the parison on the core axially in a straight path away from the mold cavity, followed by movement in a substantially arcuate path into axial alignment with the blow mold, followed by axial movement in a straight path into the blow mold. The advantage of the method and apparatus of injection blow-molding disclosed in U.S. Pat. No. 4,540,543 compared to previous injection blow-molding methods is in its reliability, preventing interruptions of the injection blow-molding operation and thereby improving efficiency. The method and apparatus as disclosed in U.S. Pat. No. 4,540,543 have been used to manufacture thin walled containers from polystyrene. In particular, disposable containers have been successfully produced from polystyrene. Such polystyrene containers are desirable because they are reusable and have aesthetic clarity. However, for producing permanent ware products which have a nominal thickness typically over 50 mils, it has been found that polystyrene was not acceptable because of breakage. When producing blow-molded permaware containers, it is often useful to incorporate onto the base indicia indicating the origin of manufacture or provide other spatial configurations to the base to aid in subsequent processing steps such as printing or packaging. However, for relatively thick bases, the fluid pressure used in blow-molding is not sufficient to adequately press the parison base against a mold and form an adequately deep molded impression on the base. Previously, such base molding step was accomplished by removing the containers from the continuous blow-molding process and stamping the base of the containers in a wholly separate apparatus. Such separate processing adds significant energy and time costs to the overall process .
Accordingly, an object of the present invention is to provide a reusable permanent ware polycarbonate container prepared by injection blow-molding wherein the container mimics glass but is not as breakable when dropped under normal usage.
Another object of the present invention is to provide a reusable, permanent ware injection blow-molded polycarbonate container that has good clarity but is more durable than other plastic containers such as those formed from polystyrene.
A further object of the present invention is to provide a process for injection blow-molding hollow polycarbonate articles characterized by a rapid, efficient and economical operating cycle.
A still further object of the present invention is to provide a process as aforesaid which is convenient and easy to use on a commercial scale and may be reliably used with high productivity.
Still yet another object of the present invention is to provide a process for injection blow-molding hollow articles characterized by a rapid, efficient and economical operating cycle such as provided by U.S. Pat. No. 4,540,543, but use resins other than polystyrene.
A still further object of this invention is to blow mold hollow permaware containers and mold the base of such containers in a continuous process without having to remove the containers from the blow-molding apparatus.
Other objects and advantages of the present invention will become apparent from the following description and drawings.
In a first aspect of the invention there is provided an injection blow-molded disposable tumbler exhibiting biaxial toughness formed from a polymeric material comprising: a base forming the bottom of the tumbler defining an outer edge thereof; a sidewall integrally formed with said base extending upwardly from the outer edge thereof defining about its upper extremity a fortified rim.
In one preferred embodiment of the present invention there is provided an injection blow-molded disposable tumbler exhibiting biaxial toughness formed from a polymeric material including: a base forming the bottom of said tumbler defining an outer edge thereof; a sidewall integrally formed with the base extending upwardly from the outer edge thereof having a thickness of from about 5 to about 50 mils defining about its upper extremity a fortified rim; the sidewall extending upwardly with a taper of from about 1.0 to about 4.5 degrees; wherein the fortified rim has a thickness of at least 2 mils greater than the adjacent portion of said sidewall over a height of at least 2 mils. More typically, the sidewall extends upwardly with a taper of from about 2.75 to about 4 degrees; and preferably the sidewall extends upwardly with a taper of about 3 degrees. The fortified rim generally has a thickness and a height of from about 1.5 to about 6 times the thickness of the adjacent portion of the sidewall; with from about 3 to about 5 times the thickness of the adjacent portion of said sidewall being more typical. The tumbler is made from a polymer which is a thermoplastic optically clear polymer, with a haze value of less than 10, usually selected from the group consisting of polystyrene, clarified polypropylene, polyesters, polycarbonates, polyacrylates and styrene acrylonitrile. The volume of said injection blow-molded tumbler is generally from about 1.5 to about 4 times the volume of an injection molded parison from which it was prepared; however, a volume of from about 1.75 to about 3 times the volume of the injection molded parison from which it was prepared is more typical, while a volume of the tumbler of about twice the volume of the injection molded parison from which it was prepared is sometimes preferred. The sidewall has a thickness of from about 10 to about 35 mils, with from about 15 to about 25 mils being more common. A thickness of about 20 mils is preferred in many instances. The sidewall may further include a pattern which alters the cylindrical character thereof over at least a portion of the sidewall which pattern is operative as a grip portion for a user. A ratio of the height of the tumbler to the inside diameter of the upper portion of the sidewall is from about 2 to about 4 in some embodiments, for example, about 3. The tumbler may have a contained volume of from about 12 to about 15 ounces, or inner volume of about 14 ounces. In some embodiments, the tumbler has a height of from about 5.75 to about 6 inches.
In another embodiment, there is provided an injection blow-molded disposable tumbler exhibiting biaxial toughness formed of a polymeric material including: (a) a base forming the bottom of the tumbler defining an outer edge thereof; (b) a sidewall integrally formed with the base extending upwardly from the outer edge thereof having a thickness of from about 5 to about 50 mils defining about its upper extremity a fortified rim; (c) the sidewall extending upwardly with a taper of from about 2.5 to about 10 degrees; wherein the fortified rim has a thickness of at least 2 mils greater than the adjacent portion of the sidewall over a height of at least 2 mils. The sidewall typically extends upwardly with a taper of from about 4.5 to about 10 degrees and preferably the sidewall extends upwardly with a taper of from about 4.5 to about 7.5 degrees. The fortified rim generally has a thickness and a height of from about 1.5 to about 6 times the thickness of the adjacent portion of the sidewall, with from about 3 to about 5 times the thickness of the adjacent portion of said sidewall being more typical. The tumbler is usually formed of optically clear polymer with a haze value of less than 10 selected from the group consisting of polystyrene, clarified polypropylene, polyesters, polycarbonates, polyacrylates and styrene acrylonitrile. The contained volume of the tumbler is generally from about 1.5 to about 4 times the volume of an injection molded parison from which it was prepared; while from about 1.75 to about 3 times the volume of the injection molded parison from which it was prepared is more typical. The tumbler is about twice the volume of the injection molded parison from which it was prepared. The tumbler sidewall has a thickness of from about 10 to about 35 mils in general, whereas, the sidewall has a thickness of from about 15 to about 25 mils in most embodiments.
Particularly preferred articles are those wherein the sidewall has a thickness of about 20 mils. The said sidewall may further include a pattern which alters the cylindrical character thereof over at least a portion of said sidewall which pattern is operative as a grip portion for a user. The tumbler typically exhibits a ratio of the height of the tumbler to the inside diameter of the upper portion of the sidewall from about 1 to about 5; whereas from about 1.3 to about 1.7 is preferred. The height of the tumbler is from about 4.6 to about 4.8 inches and it has a typical volume of from about 12 to about 16 ounces; while about 15 fluid ounces is preferred in this embodiment.
In another embodiment, there is provided an injection blow-molded disposable tumbler exhibiting biaxial toughness formed of a polymeric material including; a base forming the bottom of the tumbler defining an outer edge thereof; a sidewall integrally formed with the base extending upwardly from the outer edge thereof having a thickness of from about 5 to about 50 mils defining about its upper extremity a fortified rim; the sidewall extending upwardly with a taper of from about 1 to about 10 degrees; wherein the fortified rim has a thickness of at least 2 mils greater than the adjacent portion of the sidewall over a height of at least 2 mils, said tumbler defining a volume of at least about 16 fluid ounces. More typically, the sidewall extends upwardly with a taper of from about 2.75 to about 9 degrees and preferably with a taper of from about 5 to about 7 degrees. The fortified rim generally has thickness and a height of from about 1.5 to about 6 times the thickness of the adjacent portion of the sidewall, while a thickness and height of from about 3 to about 5 times the thickness of the adjacent portion of the sidewall is preferred. The tumbler is made from a polymeric material which is an optically clear polymer with a haze value of less than 10, selected from the group consisting of polystyrene, clarified polypropylene, polyesters, polycarbonates, polyacrylates and styrene acrylonitrile. The volume of the injection molded tumbler is typically from about 1.5 to about 4 times the volume of an injection molded parison from which it was prepared and the tumbler defines a volume of from about 16-20 fluid ounces.
The present invention is directed in still yet another embodiment to a reusable, permanent ware polylycarbonate container and method of making the polycarbonate container. The polycarbonate container mimics the clarity of glass without having the undesirable fragile property of glass and is more durable than other plastic containers such as polystyrene containers. Thus, the polycarbonate containers or tumblers have the look and feel of glass permaware and can be employed in normal usage without concern for breakage if the container is dropped. The container or tumbler includes a base, a sidewall and a fortified upper rim. The sidewall is integrally formed with the base and extends upwardly from the outer edge thereof. The sidewall is of uniform caliper or thickness of about greater than 50 thousandths of an inch (xe2x80x9cmilsxe2x80x9d) to about 500 thousandths of an inch. The tumbler preferably has a mouth (upper rim) which is about as wide or wider than the diameter of the remainder of the tumbler. Such containers are not as easily handled during the blow-molding process as blow-molded bottles and the like in which the mouth of the bottle is substantially less than the diameter of the shoulders and remaining portions of the bottle. At the upper extremity of the sidewall or mouth can be provided a fortified rim which serves to impart additional rigidity to the container. The fortified rim area has a finite width and height both of which exceed the thickness of the adjacent sidewall. While the tumbler is generally cylindrical in overall shape, the tumbler can be provided with either a uniform or non-uniform taper. The tumbler can be embossed. to impart a decorative pattern on the sidewall. The permaware polycarbonate container of the present invention is preferably prepared by a side-by-side injection blow-molding method and apparatus as disclosed in U.S. Pat. No. 4,540,543. The patented method comprises: providing an injection mold including a mold cavity formed by a mold wall and a core; injecting molten polycarbonate into the cavity to form a parison on the core; separating said parison from the mold wall by moving the parison on the core axially in a straight path away from the mold wall; providing a blow mold adjacent the mold cavity in side-by-side relationship therewith; moving the parison on the core in a substantially arcuate path into axial alignment with the blow mold; moving the parison on the core axially in a straight path into the blow mold; and expanding the parison on the core in the blow mold at a uniform temperature to form the hollow container. The apparatus comprises: an injection mold including a mold wall; a core engageable with said injection mold to form a mold cavity with the mold wall; means to inject molten polycarbonate into the mold cavity to form a parison therein; a blow mold adjacent the mold cavity in side-by-side relationship therewith; means to separate the parison from the mold wall operative to move the parison axially in a straight path away from the mold wall, followed by in a substantially arcuate path into axial alignment with the blow mold, followed by axially in a straight path into the blow mold; and means to expand the parison on the core in the blow mold to form the hollow container. The core is preferably separated from the hollow container leaving the container in the blow mold and returned to the injection mold for another cycle along paths corresponding to the foregoing path, i.e., axially, substantially arcuate and axially into the injection mold. An ejection station may then be provided adjacent the blow mold in side-by-side relationship. An ejection core can transfer the hollow container from blow mold to ejection station and return along paths corresponding to the paths of the core. In one embodiment, a second core, second ejection station, second blow mold and second ejection core are provided on the side opposed to the blow mold and ejection station for operation of an overlapping cycle. The second core and second ejection core move on paths corresponding to the paths of the core and ejection core. That is, when the core is in the blow mold the second core is in the injection mold. A major advantage of the patented blow-molding process resides in the rapid operating cycle enabled by the critical movement paths. Also, the process and apparatus are simple, convenient to operate and reliable. The resultant high productivity is a significant feature. In this aspect of the invention a method of forming a durable polycarbonate permaware container includes: (a) injecting molten polycarbonate into a mold cavity formed by a mold wall and a core to form a polycarbonate parison on the core; separating the parison from the mold wall by moving the parison on the core axially in a straight path away from the mold wall; moving the parison on the core in a substantially arcuate path into axial alignment with a blow mold which is in a side-by-side relationship with the mold cavity; moving the parison on the core axially in a straight path into the blow mold; and expanding the parison on the core in the blow mold at a uniform temperature to form a hollow container having a sidewall integrally formed to a base and a fortified rim, the sidewall having a uniform thickness of from about greater than 50 mils to about 500 mils. More typically, the sidewall has a uniform thickness of from about 75 mils to about 375 mils. In most instances, the polycarbonate is injected into the mold cavity at a temperature of from about 450xc2x0 F. to about 700xc2x0 F. and more typically, at a temperature of from about 500xc2x0 F. to about 650xc2x0 F. In general, the molten polycarbonate is injected into the mold cavity at a pressure of about 1,000 to 3,000 psi and in a preferred embodiment at an injection pressure of about 2,100 psi. The parison is expanded at a uniform temperature of from about 250xc2x0 F. to about 500xc2x0 F., at a pressure of from about 100 to about 500 psi. Typically, the polycarbonate comprises aromatic homopolycarbonate or aromatic copolycarbonate resins with a melt flow rate of from about 10 to 22 g/10 min. The polycarbonate tumbler is an injection blow-molded polycarbonate permaware hollow container comprising: a base forming the bottom of the container defining an outer edge thereof; a sidewall integrally formed with the base extending upwardly from the outer edge thereof and having a thickness of from about over 50 to about 500 mils to a fortified rim about its upper extremity. The fortified rim has a thickness of at least 2 mils greater than an adjacent portion of the sidewall over a height of at least 2 mils. Both the width and height of the fortified rim are from about 1.1 to about 4 times a thickness of an adjacent sidewall. In a particularly preferred article, both the width and the height of the fortified rim are about 100 mils and the adjacent sidewall is about 80 mils. The base is from about 1.1 to about 8 times the thickness of the sidewall. The permaware polycarbonate container is preferably one wherein the bottom of the base has integrally molded thereto indicia or a configuration different from the remaining base. A particularly preferred method of forming a container having a wall thickness greater than 50 mils comprises: blowing a parison in a blow mold shaped in the form of said container; inserting within said blown container a core which presses the base of said container against a mold face having thereon indicia or other structural configurations so as to mold said indicia or other mold configurations onto the outside surface of the base. Most preferably, the parison is formed from a polycarbonate plastic and the parison is blown by directing fluid pressure initially at the top of the parison and directing the fluid pressure from the top toward said base of said parison.
The present invention is directed in still yet another aspect to improvements in forming permaware containers by a continuous blow-molding process. The invention is also directed to improvements in the blow-molding process as disclosed in U.S. Pat. No. 4,540,543 so as to form containers from resins other than polystyrene.
The present invention is characterized in these latter aspects as a side-by-side injection blow-molding method and apparatus and is at least in part disclosed in U.S. Pat. No. 4,540,543. The patented method comprises: providing an injection mold including a mold cavity formed by a mold wall and a core; injecting molten resin into the cavity to form a parison on the core; separating said parison from the mold wall by moving the parison on the core axially in a straight path away from the mold wall; providing a blow mold adjacent the mold cavity in side-by-side relationship therewith; moving the parison on the core in a substantially arcuate path into axial alignment with the blow mold; moving the parison on the core axially in a straight path into the blow mold; and expanding the parison on the core in the blow mold at a uniform temperature to form the hollow container. The apparatus comprises: an injection mold including a mold wall; a core engageable with said injection mold to form a mold cavity with the mold wall; means to inject molten resin into the mold cavity to form a parison therein; a blow mold adjacent the mold cavity in side-by-side relationship therewith; means to separate the parison from the mold wall operative to move the parison on the core axially in a straight path away from the. mold wall, followed by in a substantially arcuate path into axial alignment with the blow mold, followed by axially in a straight path into the blow mold; and means to expand the parison on the core in the blow mold to form the hollow container. The core is preferably separated from the hollow container leaving the container in the blow mold and returned to the injection mold for another cycle along paths corresponding to the foregoing path, i.e., axially, substantially arcuate and axially into the injection mold. An ejection station may then be provided adjacent the blow mold in side-by-side relationship. An ejection core can transfer the hollow container from blow mold to ejection station and return along paths corresponding to the paths of the core.
In an additional embodiment, a second core, second ejection-station, second blow mold and second ejection core are provided on the side opposed to the blow mold and ejection station for operation of an overlapping cycle. The second core and second ejection core move on paths corresponding to the paths of the core and ejection core. That is, when the core is in the blow mold the second core is in the injection mold. Obviously, additional cores, ejection stations, blow molds, and ejection cores can be provided and operated in an overlapping cycle to increase productivity. A major advantage of the patented blow-molding process resides in the rapid operating cycle enabled by the critical movement paths. Also, the process and apparatus are simple, convenient to operate and reliable. The resultant high productivity is a significant feature.
In accordance with this invention, the above patented process is used to form injection blow-molded containers formed of polymers other than polystyrene. Thus, it has been found that the above patented process can be used to form clear containers from resins such as polycarbonate, polyethylene terephthalate, polycarbonate/ABS mixed resin, acrylic resins, clarified (amorphous) polypropylene and polyvinylchloride. Additionally, the present invention is directed to a process of molding the base of a blown container without removing the container from the blow mold. In this invention, after the parison is blown to the container in the blow cavity, an ejection core is inserted into the container while the container remains in the blow cavity. The ejection core pushes the base of the container against a mold opposed to the outside surface of the container base. The mechanical pressure of the ejection core against the container base is sufficient to adequately transfer the molded configuration of the mold onto the outside surface of the container base. Once the base is molded, the container can be removed from the blow cavity by the ejection core on a continuous basis. The continuous process saves considerable time and energy over prior art processes which required a stamping step after the container had been removed from the blow cavity. There is thus provided a method of forming a container comprising: injecting molten resin into a mold cavity formed by a mold wall and a core to form a resinous parison on the core; separating the parison from the mold wall by moving the parison on the core axially in a straight path away from the mold wall; moving the parison on the core in a substantially arcuate path into axial alignment with a blow mold which is in a side-by-side relationship with the mold cavity; moving the parison on the core axially in a straight path into the blow mold; and expanding the parison on the core in the blow mold at a uniform temperature to form a hollow container; wherein the resin is selected from the group consisting of filled polystyrene, filled and non-filled polycarbonate, polyethylene terephthalate, polycarbonate and ABS mixtures, acrylic resins, clarified polypropylene and polyvinylchloride. The filled resins contain up to 5 wt. % of nanometer-sized particles which may comprise a clay. In one embodiment, a transparent drinking tumbler is comprised of polystyrene filled with nanometer-sized particles having a size within the range of visible-light wavelengths. In another aspect, there is provided a method of forming a container having a wall thickness greater than 50 mils, the container containing sidewalls and an integrally formed base, the method comprising: blowing a parison in a blow mold shaped in the form of the container to form a hollow container, inserting within the hollow container, which remains in the blow mold, a core which presses the base of the container against a mold face having thereon indicia or other structural configurations so as to mold the indicia or other mold configurations onto the outside surface of the base. Another method involves forming a container comprising: (a) injecting molten resin into a mold cavity formed by a mold wall and a core to form a resinous parison on the core; (b) separating the parison from the mold wall by moving the parison on the core axially in a straight path away from the mold wall; (c) moving the parison on the core in a substantially arcuate path into axial alignment with a blow mold which is in a side-by-side relationship with the mold cavity; (d) moving the parison on the core axially in a straight path into the blow mold; and (e) expanding the parison on the core in the blow mold by directing fluid initially at the top of the parison and directing the fluid pressure from the top toward the base of the parison at a uniform temperature to form a hollow container; there the resin is selected from the group consisting of polycarbonate, polyethylene terephthalate, polycarbonate and ABS mixtures, acrylic resins, clarified polypropylene and polyvinylchloride.
In still further embodiments of the present invention, there is provided an injection blow-molded tumbler with a fortified rim having a thickness greater than the adjacent sidewall formed of a polymeric material including a styrene/butadiene copolymer. In general, the copolymer is from about 2 to about 40 percent by weight butadiene residue with from about 8 to about 15 percent by weight butadiene residue in the composition being typical. The tumbler may consist entirely of butadiene/styrene copolymer, or the copolymer may be blended with other polymers, for example, polystyrene.
Alternatively, polystyrene or other polymeric composition may be provided with an impact modifier. Typically, impact modifiers may be core-shell polymers, olefin containing copolymers, rubber polymers, rubber copolymers, styrene containing copolymers and mixtures thereof. So also, the inventive tumblers may be made from filled polymeric compositions including conventional filler such as mica, talc and the like. Suitable filled compositions may include from 5 to 50 weight percent filler, with from about 8 to about 20 percent filler being more typical. From about 10 to about 15 weight percent filler is perhaps most suitable for the injection blow-molded tumblers.